Author(s): John N. Kateregga, Prossy N. Nantale and James G. Ndukui*
Ginger (Zingiber officinale) has for long been used as an anti-sore throat remedy in African societies. This study evaluated the in-vitro activity of ethanol and hexane rhizome extracts of ginger against Streptococcus pyogenes, the most common bacterial cause of the condition and determined the levels of selected phytochemicals in the extracts. Ginger was obtained from the markets in Kampala, dried for 2 weeks, and then ground into a fine powder using mortar and pestle. After cold maceration of the powder with ethanol or hexane, the filtrates were evaporated to slurry with a rotary evaporator. Fresh crude extracts were prepared immediately prior to use. The anti-Streptococcus pyogenes activity was evaluated using the Agar well diffusion and the peptone water serial dilution methods and inhibition zone diameters and minimum inhibitory concentrations of the extracts were determined. Phytochemical profiles of extracts were qualitatively assessed. Both extracts inhibited S. pyogenes growth but activity was higher for the ethanol extract than for the hexane extract. While this difference was not statistically significant (p > 0.05) for the 400 mg/ml concentration of the extracts it was significant at the 800 mg/ml concentrations. The MIC for both extracts was 0.2 g/ml. Both extracts showed similar phytochemical profiles with rich tannin content and rather low levels of saponins, steroid glycosides and triterpenes. The study demonstrates the anti-Streptococcus pyogenes activity of the rhizome of Z. officinale and its potential as a possible source of a Strep throat remedy.